This is not the Marlboro cowboy puffing on his cigarette, but volcanic smoke rings ejected from Mt Etna.
Look at this stunning picture of the volcano smoke ring phenomenon captured by German volcanologist Chris Weber off the east coast of Sicily.
Mount Etna is an active volcano in Sicily. And sometimes it puffs strange and mysterious smoke ring in the sky. These great images show a perfectly formed smoke ring which was puffed out by Mount Etna. The smoke ring was caught floating in the blue sky off the east coast of Sicily, Italy by volcanologist Chris Weber, 45, from Stuttgart in Germany. The smoke ring was measuring about 50m wide.
Here the explanation:
Similar to how smokers make smoke rings with their mouths – the volcano has a deep crater pit with circular vertical walls like a chimney. Because the air in the centre of the ring is forced out faster, a circular vortex is formed which keeps the rounded shaper of the smoke ring.